Make different pointer for every user,How?

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Hey All

I am facing a problem for creating the struct pointer different for every user

C++

#include<conio.h>
struct mine_struct
{
    int a;

};
int main()
{
    for(int i=0;i<=10;i++)
    {
    int num;
    printf("Hey user please enter the no\n");
    scanf("%d",&num);
    if(num==1)
                {
                    //create a struct pointer for every user dynamically
                    //access the a variable

                    //if i do like this
                        struct mine_struct *p =NULL;
                        p->a=21;

                        //Then p i allocated for every 10 runs i want to create the different pointer for different user and also destroy them
                }
    else
        {
            printf("you have not entered the valid no\n");
        }
    }



return 0;
}

Posted 14-Jan-14 22:39pm

Robert Clove

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CPallini · Answer 1 · 2014-01-14T23:08:00

If you have a fixed number of users (say 10) then declare

C

#define USERS 10
struct mine_struct *p[USERS];

and then, at runtime, create and fill the details of proper item, e.g.

C

if (user == 5)
{
  p[user] =(struct mine_struct *) malloc(sizeof(struct mine_struct));
  if (p[user])
    p[user]->a = 21;
}

Then, when you don't need anymore it

C

if ( p[user] )
{
  free(p[user]);
  p[user] == NULL;
}

OriginalGriff · Answer 2 · 2014-01-14T23:11:00

You can't do that: you are specifically setting the value of the pointer to null and then trying to access data via it - that won't work under any circumstances.
I would suggest that you need to look at malloc[^] and free[^] but I can't help you much further as your description of what you want to do makes no sense when viewed with your code...

Make different pointer for every user,How?

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